After using some old ski socks as liners for my Scarpa Inverno mountaineering boots, which contributed to nasty abraisions on the insides of both of my heels, I decided it was time to invest in the real thing. So far, using these in light weight hiking boots, packing 42 pounds, and one short section in the big boots, no hot spots at all. I have size 12.5 US feet and size XL fits well.

Smartwool has done a good job with making a liner sock with seams that don't chafe. I've got a couple of pairs of liner socks from other companies, and they all have an irritating toe seam, but the Smartwools are comfortable and I can wear them without a problem.

Definitely a liner and only for hiking, not other winter sports. The size seemed to run a little small as well. I had hoped to use it skiing, but with the small size it ended up making my feet feel cramped. This wasn't an issue just hiking. Good temp regulation.

These are not just hiking boot liners. They are thebest wearing and most comfortable every day sox Ihave. They are light enough to wear all year aroundThey wash exceedingly well with no shrinkage. I haveyet to see a sign of wear. And....if you have trouble bending over to put your sox on (hip replacements, etc. they go on easily.

While wearing "normal" hiking socks, I had been very aware that I was in hiking boots from the minute I put them on. In these (coupled with the SmartWool PhD Outdoor Medium Crew socks) my feet felt fantastic. Even after hours on the trail, my feet felt better than they did in other socks.

Used them on an excursion to Joshua Tree National Park in California. I was a bit skeptical at first about using under socks. I used the hiking Smartwool socks as my outer layer and had done just fine hiking with those, but due to the intensity of this trip, decided to try them out. They worked phenomenal! I'm so glad I picked these up. They kept my feet dry and comfy over some unforgiving terrain.